TW202103345A - Wafer scale ultrasonic sensing device and manufacation method thereof - Google Patents

Abstract

A wafer scale ultrasonic sensing device includes a substrate assembly, an ultrasonic component, a first protective layer, a first conductive line, a second conductive line, a second protective layer, a conductive material, electrical connection layers, and soldering portions. The substrate assembly includes a first wafer and a second wafer, and the second wafer covers the recess on the first wafer to define the hollow chamber. The projection of ultrasound element and the hollow chamber are overlapped. The first protective layer surrounds the ultrasonic element. The first wafer, the second wafer, and the first protective layer are coplanar with the first conductive line on a first side surface and coplanar with the second conductive line on a second side surface. The second protective layer has an opening in which the conductive material contacts the ultrasonic element. The electrical connection layer is disposed on the first side surface and the second side surface, and the soldering portions are respectively connected to the electrical connection layers.

Description

Wafer-level ultrasonic sensing device and manufacturing method thereof

This application relates to the field of ultrasonic transmission, in particular to a wafer-level ultrasonic sensing device and a manufacturing method thereof.

As the functions of 3C products become more convenient, smart electronic devices such as smart phones and tablets, or laptops, have become essential tools for life and work. Since work data, personal data, and even financial data are all stored in such electronic products, the loss of data may cause heavy losses to users. Therefore, in addition to the traditional account number and password, the user's physiological information is usually used to authenticate and identify the user, so as to achieve the function of sufficient anti-counterfeiting and avoiding data loss.

In physiological information, the most commonly used method is fingerprint recognition. Fingerprint recognition relies on sending a super signal to the finger, and then receiving the strength of the signal reflected by the peaks and valleys of the fingerprint to recognize the fingerprint. At present, the ultrasonic method can get a better way, even when the finger is wet, it can be effectively identified. However, wafer-level ultrasonic sensing components are currently used, and the yield rate of the current process is still not high, which will directly affect the production cost and sales price. If the necessary configuration components for 3C products are required in the future, there is still a lot of room for improvement.

Here, a wafer-level ultrasonic sensing device is provided. The wafer-level ultrasonic sensing device includes a substrate assembly, an ultrasonic element, a first protective layer, a first conductive circuit, a second conductive circuit, a second protective layer, and a conductive material. , Two electrical connection layers and two welding parts.

The substrate assembly includes a first wafer and a second wafer. The first wafer is provided with a groove, and the second wafer is bonded with the first wafer and covers the groove, thereby defining a hollow cavity. The ultrasonic element is located on the second wafer, and the projection of the ultrasonic element and the hollow cavity is superimposed in the vertical direction. The first protective layer is located on the first surface of the second wafer and surrounds the ultrasonic element. The first conductive circuit and the second conductive circuit are located on the first protective layer and are respectively connected to the upper surface of the ultrasonic element, wherein the first wafer, the second wafer, the first protective layer and the first conductive circuit are on the first side The surface is coplanar; the first wafer, the second wafer, the first protective layer and the second conductive circuit are coplanar on the second side surface.

The second protective layer covers the first conductive circuit and the second conductive circuit, the second protective layer has an opening, and the upper surface of the ultrasonic element corresponds to the opening. The conductive material is located in the opening and contacts the upper surface of the ultrasonic element. The two electrical connection layers are respectively arranged on the first side surface and the second side surface, and are connected to the first conductive circuit and the second conductive circuit. The two soldering parts are located on a bottom surface of the first wafer and are respectively connected to the two electrical connection layers.

In some embodiments, the ultrasonic element includes a first piezoelectric layer, a first electrode, a second piezoelectric layer, and a second electrode sequentially stacked on a second wafer, wherein the second piezoelectric layer and the second electrode are not Part of the upper surface of the first electrode is covered, the conductive material contacts the second electrode, and the first electrode and the second electrode are respectively connected to the first conductive circuit and the second conductive circuit.

In some embodiments, the ultrasonic element includes a first ultrasonic unit and a second ultrasonic unit. The first ultrasonic unit includes a first piezoelectric layer and a first electrode, the first piezoelectric layer is located on the second wafer, and the first piezoelectric layer and the first protective layer have a first contact hole that communicates with each other. The first electrode is wrapped in the first piezoelectric layer, and a part of the first electrode is exposed to the first contact hole, and a part of the first conductive circuit is located in the first contact hole and is connected to the first electrode. The second ultrasonic unit does not overlap with the first ultrasonic unit in a direction perpendicular to the second wafer, and the second ultrasonic unit includes a second piezoelectric layer, a second circuit pattern layer, and a second electrode. The second piezoelectric layer is located on the second wafer, and the second piezoelectric layer and the first piezoelectric layer are the same layer and separated from each other. The second circuit pattern layer is wrapped in the second piezoelectric layer, and the second circuit pattern layer and the first electrode are the same layer and separated from each other. The second electrode is located on the second piezoelectric layer, the first protection layer has a second contact hole, the second contact hole communicates with the opening, a part of the second conductive circuit is located in the second contact hole and is connected to the second electrode, the conductive material A part of is filled in the second contact hole and is in contact with the second electrode.

In some embodiments, the conductive material is polydimethylsiloxane.

Here, a manufacturing method of a wafer-level ultrasonic sensing device is also provided. The manufacturing method of a wafer-level ultrasonic sensing device includes a substrate preparation step, a bonding step, an ultrasonic element forming step, a first protective layer forming step, a wiring connection step, a second protective layer forming step, an opening opening step, a removing step, The electrical connection layer forming step, the soldering portion forming step, and the conductive material filling step.

The substrate preparation step is to provide a first wafer and a composite substrate, the first wafer is provided with a groove, and the composite substrate includes a second wafer, an insulating layer, and a third wafer stacked in sequence. The bonding step is an anodic bonding of the second wafer and the first wafer, the second wafer covers the groove, and the groove forms a hollow cavity. The removing step is to remove the insulating layer and the third wafer thereon to complete the substrate assembly.

The ultrasonic element forming step is to form the ultrasonic element on the second wafer, wherein the ultrasonic element and the projection of the hollow cavity are superimposed in the vertical direction, and the ultrasonic element includes a first electrode and a second electrode not connected to the first electrode. The first protective layer forming step is to form a first protective layer on the upper surface of the ultrasonic element and the first surface of the second wafer. The first protective layer has a first contact hole and a second contact hole, a part of the first electrode and the first surface of the second wafer. A part of the two electrodes are respectively exposed to the first contact hole and the second contact hole.

The circuit connection step is to form the first conductive circuit and the second conductive circuit on the first protective layer. Part of the first conductive circuit and the second conductive circuit are respectively arranged in the first contact hole and the second contact hole, and are respectively connected to the first electrode and the second electrode of the ultrasonic element. The second protective layer forming step is to form a second protective layer to cover the first conductive circuit and the second conductive circuit. The opening opening step is to open an opening on the second protective layer, and at least a part of the second electrode is exposed in the opening.

The removing step is to remove a part of the substrate assembly, a part of the first protective layer, a part of the first conductive circuit, and a part of the second conductive circuit to form a first wafer, a second wafer, a first protective layer, and a second conductive circuit. A first side surface of the conductive circuit is coplanar, and a second side surface of the first wafer, the second wafer, the first protective layer, and the second conductive circuit are coplanar. The step of forming the electrical connection layer is to form electrical connection layers on the first side surface and the second side surface respectively, and the electrical connection layers are respectively connected to the first conductive circuit and the second conductive circuit. In the step of forming the soldering portion, two soldering portions are formed on the surface of the first wafer crystal plate, and each soldering portion is stacked and connected to each electrical connection layer. The conductive material filling step fills the opening with conductive material, and the conductive material contacts the upper surface of the ultrasonic element.

In some embodiments, a polishing step is further included before the bonding step, and the polishing step reduces the thickness of the second wafer.

In some embodiments, after the opening opening step, a carrier board covering step is further included. The carrier board covering step is to cover the carrier board on the second protective layer and the opening to shield the opening; and after the welding portion forming step, it further includes a carrier board. The board removal step is to remove the carrier board to expose the opening.

In some embodiments, the ultrasonic element forming step includes: sequentially forming a first piezoelectric layer, a first electrode, a second piezoelectric layer, and a second electrode on the second wafer; and removing the second piezoelectric layer and the second piezoelectric layer. A part of the two electrodes is such that the second piezoelectric layer and the second electrode do not cover part of the upper surface of the first electrode, and in the opening opening step, the first protective layer above the second electrode is further removed.

In some embodiments, the ultrasonic element forming step includes: sequentially forming a first piezoelectric material layer and a first electrode material layer on the second wafer; patterning the first piezoelectric material layer and the first electrode material layer, To form a first bottom piezoelectric layer and a second bottom piezoelectric layer separated from each other, and a first electrode and a second circuit pattern layer stacked on the first bottom piezoelectric layer and the second bottom piezoelectric layer, respectively; A second piezoelectric material layer and a second electrode material layer are sequentially formed on the first electrode and the second circuit pattern layer; and the second piezoelectric material layer and the second electrode material layer are patterned to form a second layer separated from each other A piezoelectric layer and a second piezoelectric layer, and a second electrode formed on the second piezoelectric layer, wherein the first electrode is covered in the first piezoelectric layer, and the second circuit pattern layer is covered in Inside the second piezoelectric layer.

In more detail, in some embodiments, a first protective material layer is formed on the first piezoelectric layer, the second piezoelectric layer, and the second electrode; and the first protective material layer is perforated to form the first protective material The layer is patterned into a first protective layer, wherein the first protective layer includes a first contact hole and a second contact hole. The first contact hole penetrates the first protective layer and the first piezoelectric layer to expose a part of the first electrode to the first In a contact hole, the second contact hole penetrates the first protection layer, so that a part of the second electrode is exposed to the second contact hole.

In some embodiments, the bonding step is performed in an evacuated environment.

To sum up, the wafer-level ultrasonic sensing device uses the hollow cavity and the difference in the conductive material to make the ultrasonic signal transmitted in it have different speeds, and can achieve effective signal resolution. In addition, through the arrangement and manufacturing method of the substrate assembly, the stability of alignment and bonding can be effectively improved, and the overall production yield can be effectively improved, thereby reducing the overall cost.

FIG. 1 is a schematic cross-sectional view of a first embodiment of a wafer-level ultrasonic sensing device. As shown in FIG. 1, the wafer-level ultrasonic sensing device 1 of the first embodiment includes a substrate assembly 10, an ultrasonic element 22, a first protective layer 30, a first conductive circuit 41, a second conductive circuit 43, and a second protective layer. 50. The conductive material 60, the first electrical connection layer 71, the second electrical connection layer 73, and the second welding portion 80. The substrate assembly 10 is a composite substrate, including a first wafer 11 and a second wafer 13. The first wafer 11 is provided with a groove 111, and the second wafer 13 and the first wafer 11 are joined by anodizing. It covers the groove 111 and defines a hollow cavity 111. It is stated here that the groove 111 and the hollow cavity 111 are substantially the same space, so the same component numbers are used.

The ultrasonic element 22 is located on the second wafer 13, more specifically, on the first surface 13a of the second wafer. The projection of the ultrasonic element 22 and the projection of the hollow cavity 111 overlap in the vertical direction. That is, the projection of the ultrasonic element 22 and the projection of the hollow cavity 111 are at least partially superimposed on a virtual plane.

The first protective layer 30 is located on the first surface 13 a of the second wafer 13 and surrounds the ultrasonic element 22. The first conductive circuit 41 and the second conductive circuit 43 are located on the first protective layer 30 and are respectively connected to the upper surfaces 222a, 224a of the ultrasonic element 22. In more detail, the first conductive circuit 41 is connected to the first of the ultrasonic element 22. The upper surface 222 a of the electrode 222, and the second conductive circuit 43 is connected to the upper surface 224 a of the second electrode 224 of the ultrasonic element 22. The first wafer 11, the second wafer 13, the first protective layer 30, and the first conductive circuit 41 are coplanar on the first side surface 101; and the first wafer 11, the second wafer 13, and the first protective layer 30 and the second conductive circuit 43 are coplanar on the second side surface 103. In more detail, the first side surface 101 and the second side surface 103 are two inclined surfaces of the wafer-level ultrasonic sensing device 1, the width of which gradually increases from the first conductive circuit 41 and the second conductive circuit 43 toward the first wafer 11. To shrink.

The second protective layer 50 covers the first conductive circuit 41 and the second conductive circuit 43. The second protective layer 50 has an opening 55, and the upper surface 224 a of the ultrasonic element 22 corresponds to the opening 55. The conductive material 60 is located in the opening 55 and contacts the upper surface 224 a of the ultrasonic element 22. The first electrical connection layer 71 and the second electrical connection layer 73 are respectively disposed on the first side surface 101 and the second side surface 103, and are respectively connected to the first conductive circuit 41 and the second conductive circuit 43. The two soldering parts 80 are located on the bottom surface 11 b of the first wafer 11 and are respectively connected to the first electrical connection layer 71 and the second electrical connection layer 73. The soldering part 80 can be soldered to a circuit board or a special chip, and provides an electrical circuit for controlling the wafer-level ultrasonic sensing device 1.

In the first embodiment, the ultrasonic element 22 includes a first piezoelectric layer 221, a first electrode 222, a second piezoelectric layer 223, and a second electrode 224 sequentially stacked on the second wafer 13, wherein the second piezoelectric layer The electrical layer 223 and the second electrode 224 do not cover part of the upper surface 222 a of the first electrode 222. The conductive material 60 contacts the upper surface 224a of the second electrode 224, and the first electrode 222 and the second electrode 224 are connected to the first conductive circuit 41 and the second conductive circuit 43, respectively.

In more detail, the purpose of the conductive material 60 located in the opening 55 and contacting the upper surface 224a of the second electrode 224 is to enable the ultrasonic signal generated by the ultrasonic element 22 to be better transmitted to the finger through the conductive material 60. In one embodiment, the conductive material 60 may be polydimethylsiloxane (PDMS), however, this is only an example, not a limitation.

2 is a schematic cross-sectional view of a second embodiment of a wafer-level ultrasonic sensing device. As shown in FIG. 2 and referring to FIG. 1 at the same time, the difference between the second embodiment and the first embodiment is mainly the ultrasonic element. The ultrasonic element 20 of the second embodiment includes a first ultrasonic unit 21 and a second ultrasonic unit 23. The first ultrasonic unit 21 includes a first piezoelectric layer 215 and a first electrode 213. The first piezoelectric layer 215 is located on the second wafer 13, and the first piezoelectric layer 215 and the first protective layer 30 have connected first contact holes 30A, and the first electrode 213 is covered on the first piezoelectric layer 215 A part of the first electrode 213 is exposed to the first contact hole 30B, and a part of the first conductive circuit 41 is located in the first contact hole 30A and connected to the first electrode 213. In more detail, the first ultrasonic unit 21 further includes a first bottom piezoelectric layer 211. The first bottom piezoelectric layer 211 is disposed on the second wafer 13, the first electrode 213 is stacked on the first bottom piezoelectric layer 211, and the first bottom piezoelectric layer 211 and the first electrode 213 are covered together Inside the first piezoelectric layer 215.

The second ultrasonic unit 23 does not overlap with the first ultrasonic unit 21 in a direction perpendicular to the second wafer 13. The second ultrasonic unit 23 includes a second piezoelectric layer 235, a second circuit pattern layer 233 and a second electrode 237. The second piezoelectric layer 235 is located on the second wafer 13, and the second piezoelectric layer 235 and the first piezoelectric layer 215 are the same layer and separated from each other. The second circuit pattern layer 233 is covered in the second piezoelectric layer 235, and the second circuit pattern layer 233 and the first electrode 213 are the same layer and separated from each other. The second electrode 237 is located on the second piezoelectric layer 235, the first protection layer 30 has a second contact hole 30B, and the second contact hole 30B communicates with the opening 55. A part of the second conductive circuit 43 is located in the second contact hole 30B and is connected to the second electrode 237, and a part of the conductive material 60 is filled in the second contact hole 30B and is in contact with the second electrode 237. In more detail, the second ultrasonic unit 23 further includes a second bottom piezoelectric layer 231. The second bottom piezoelectric layer 231 is disposed on the second wafer 13, the second electrode 237 is stacked on the second bottom piezoelectric layer 231, and the second bottom piezoelectric layer 231 and the second electrode 237 are covered together Inside the second piezoelectric layer 235.

Here, the first bottom piezoelectric layer 211, the second bottom piezoelectric layer 233, the first piezoelectric layer 215/221, and the second piezoelectric layer 235/223 of the first and second embodiments can be used The materials are piezoelectric materials such as aluminum nitride (AlN), zinc oxide (ZnO), and lead zirconate titanate (PZT). The material of the first protection layer 30 and the second protection layer 50 may be silicon dioxide (SiO ₂ ). In addition, the materials of the first electrode 213/222, the second circuit pattern layer 233, and the second electrode 237 may be aluminum (Al), tungsten (W), molybdenum (Mo), platinum (Pt), gold (Au), and silver. (Ag), copper (Cu) and other conductive materials. But this is only for profit, not for restriction.

3A to FIG. 3O are schematic cross-sectional views corresponding to each step of the manufacturing method of the first embodiment of the wafer-level ultrasonic sensing device. The manufacturing method of a wafer-level ultrasonic sensing device includes a substrate preparation step, a bonding step, an ultrasonic element forming step, a first protective layer forming step, a wiring connection step, a second protective layer forming step, an opening opening step, a removing step, The electrical connection layer forming step, the soldering portion forming step, and the conductive material filling step. Hereinafter, the manufacturing method of the wafer-level ultrasonic sensing device 1 of the first embodiment will be explained with reference to the drawings.

As shown in FIGS. 3A and 3C, the substrate preparation step is to provide a first wafer 11 and a composite substrate 10B. The first wafer 11 is provided with a groove 111, and the composite substrate 10B includes a second wafer 13, which is sequentially stacked. The insulating layer 15 and the third wafer 17. Here, the composite substrate 10B may be a double-layer silicon on insulator (SOI) substrate.

As shown in FIG. 3D, the bonding step is to anodic bonding the second wafer 13 and the first wafer 11, and the second wafer 13 covers the groove 111 to form a hollow cavity 111. In some embodiments, the joining step is performed in an evacuated environment, so that the hollow cavity 111 is in a vacuum state. In order to consider the thickness of the product, further, a polishing step and a polishing step are included after the substrate preparation step and before the bonding step to reduce the thickness of the second wafer 13. The polishing step can be thinned by Chemical Mechanical Polishing (CMP), however, this is only an example, not a limitation. As shown in FIG. 3E, the removing step is to remove the insulating layer 15 and the third wafer 17 thereon to complete the substrate assembly 10. Here, for example, when the insulating layer 15 is silicon dioxide, the insulating layer 15 can be removed by etching with hydrofluoric acid (HF), and the third wafer 17 thereon can be removed at the same time.

Referring to FIGS. 3F and 3G, and also referring to FIG. 1, the ultrasonic element forming step in the first embodiment is to form the ultrasonic element 22 on the second wafer 13, wherein the projection of the ultrasonic element 22 and the projection of the hollow cavity are in the vertical direction The upper overlap, and the ultrasonic element 22 includes a first electrode 222 and a second electrode 224 that is not connected to the first electrode 222.

In more detail, in the first embodiment, the first piezoelectric layer 221, the first electrode 222, the second piezoelectric layer 223, and the second electrode 224 are formed in sequence on the second wafer 13 first. Then, a part of the second piezoelectric layer 223 and the second electrode 224 is removed, so that the second piezoelectric layer 223 and the second electrode 224 do not cover part of the upper surface 222 a of the first electrode 222. In some embodiments, when the second piezoelectric layer 223 and the second electrode 224 are removed, a part of the first piezoelectric layer 221 and the first electrode 222 may also be removed.

As shown in FIG. 3H, the first protective layer forming step is to form the first protective layer 30 on the upper surfaces 222 a and 224 a of the ultrasonic element 22 and the first surface 13 a of the second wafer 13. The first protection layer 30 has a first contact hole 30A and a second contact hole 30B. A part of the first electrode 222 and a part of the second electrode 224 are exposed to the first contact hole 30A and the second contact hole 30B, respectively. The step of forming the first protective layer can be achieved by first coating the protective layer material, and then forming the first protective layer 30 by means of drilling, laser opening, or the like.

As shown in FIG. 3I, the circuit connection step is to form the first conductive circuit 41 and the second conductive circuit 43 on the first protective layer 30. Part of the first conductive circuit 41 and the second conductive circuit 43 are respectively disposed in the first contact hole 30A and the second contact hole 30B, and are respectively connected to the first electrode 222 and the second electrode 224 of the ultrasonic element 22. As shown in FIG. 3J, the second protective layer forming step is to form a second protective layer 50 to cover the first conductive circuit 41 and the second conductive circuit 43. In some embodiments, the second protective layer 50 and the first protective layer 30 may be the same material.

As shown in FIG. 3K, the opening opening step is to open an opening 55 on the second protective layer 50, and at least a part of the second electrode 224 is exposed in the opening 55. In more detail, in the opening opening step, the opening further removes the first protective layer 30 above the second electrode 224 so that the upper surface 224a of the second electrode 224 is exposed.

As shown in FIG. 3M, the removing step is to remove a part of the substrate assembly 10, a part of the first protective layer 30, a part of the first conductive circuit 41, and a part of the second conductive circuit 43 to form the first wafer 11, Coplanar first side surface 101 of the second wafer 13, the first protective layer 30, and the first conductive circuit 41, and the first wafer 11, the second wafer 13, the first protective layer 30, and the second conductive circuit 43 The second side surface 103 is coplanar. Here, the first side surface 101 and the second side surface 103 are the two inclined surfaces of the wafer-level ultrasonic sensing device 1, the width of which gradually increases from the first conductive circuit 41 and the second conductive circuit 43 toward the first wafer 11. reduce.

In some embodiments, in order to ensure the mechanical strength during removal, before the removal step, as shown in FIG. 3L, a carrier board covering step may be further included after the opening opening step. The carrier board covering step is to cover the carrier board 600. On the second protective layer 50 to cover the opening 55.

As shown in FIG. 3N, the step of forming the electrical connection layer is to form the first electrical connection layer 71 and the second electrical connection layer 73 on the first side surface 101 and the second side surface 103, respectively. The first electrical connection layer 71 and the second electrical connection layer 73 are respectively connected to the first conductive circuit 41 and the second conductive circuit 43. Finally, as shown in FIG. 30, in the step of forming the soldering portion, two soldering portions 80 are formed on the bottom surface 11 b of the first wafer 11, and the soldering portions 80 are stacked to connect the first electrical connection layer 71 and the second electrical connection layer 73. In the conductive material filling step, the conductive material 60 is filled in the opening 55, and the conductive material 60 contacts the upper surface 224 a of the ultrasonic element 22. In more detail, the upper surface 224a of the second electrode 224 is contacted. In the embodiment covered with the carrier board 600, after the step of forming the welding portion, a carrier board removal step is further included to remove the carrier board 600 to expose the opening 55.

4A to 4H are schematic cross-sectional diagrams corresponding to the steps in the second embodiment of the wafer-level ultrasonic sensing device that are different from the first embodiment in the manufacturing method. The main difference between the second embodiment and the first embodiment lies in the part of the ultrasonic element 22, and the base material preparation step and the joining step before the ultrasonic element formation step of the first embodiment are roughly the same as those in FIGS. 3A to 3E. The steps except for the steps, the steps for forming the electrical connection layer, the steps for forming the soldering portion, and the steps for filling the conductive material are also roughly the same as those in FIGS. 3M to 3O, which will not be repeated here, and only the differences from the first embodiment will be performed. Description.

As shown in FIG. 4A, the ultrasonic element forming step of the second embodiment includes: sequentially forming a first piezoelectric material layer 201 and a first electrode material layer 203 on the second wafer 13. Next, as shown in FIG. 4B, the first piezoelectric material layer 201 and the first electrode material layer 203 are patterned to form a first bottom piezoelectric layer 211 and a second bottom piezoelectric layer 231 that are separated from each other, and are respectively stacked on The first electrode 213 and the second circuit pattern layer 233 on the first bottom piezoelectric layer 211 and the second bottom piezoelectric layer 231.

As shown in FIG. 4C, a second piezoelectric material layer 205 and a second electrode material layer 207 are sequentially formed on the first electrode 213 and the second circuit pattern layer 233. At this time, the second piezoelectric material layer 205 and the second electrode material layer 207 cover the first bottom piezoelectric layer 211, the second bottom piezoelectric layer 231, the first electrode 213, and the second circuit pattern layer 233.

Next, as shown in FIG. 4D, the second piezoelectric material layer 205 and the second electrode material layer 207 are patterned to form a first piezoelectric layer 215 and a second piezoelectric layer 235 that are separated from each other, and are formed in the second piezoelectric layer. The second electrode 237 on the electrical layer 235. At this time, the first electrode 213 is covered in the first piezoelectric layer 235, and the second circuit pattern layer 233 is covered in the second piezoelectric layer 235. In this way, the first ultrasonic unit 21 and the second ultrasonic unit 23 are formed.

Next, as shown in FIG. 4E, the first protective layer forming step in the second embodiment is the same as in the first embodiment, forming a first protective material layer on the first piezoelectric layer 215, the second piezoelectric layer 235, and the second electrode 237 on. The first protective material layer is perforated and patterned into the first protective layer 30. The first protection layer 30 includes a first contact hole 30A and a second contact hole 30A. The first contact hole 30A penetrates the first protection layer 30, and further penetrates the first piezoelectric layer 231, so that a part of the first electrode 213 is exposed to the first In the contact hole 30A, the second contact hole 30B penetrates the first protection layer 30 so that a part of the second electrode 237 is exposed to the second contact hole 30B.

Next, as shown in FIG. 4F, as in the first embodiment, the circuit connection step is to form the first conductive circuit 41 and the second conductive circuit 43 on the first protective layer 30. Part of the first conductive circuit 41 and the second conductive circuit 43 are respectively disposed in the first contact hole 30A and the second contact hole 30B, and are respectively connected to the first electrode 213 and the second electrode 237 of the ultrasonic element 20.

As shown in FIG. 4G, the second protective layer forming step is to form a second protective layer 50 to cover the first conductive circuit 41, the second conductive circuit 43, and the second electrode 237 that is not connected to the second conductive circuit 43. Finally, as shown in FIG. 4H, the opening opening step is to open an opening 55 on the second protection layer 50, and at least a part of the second electrode 224 is exposed in the opening 55. In more detail, the opening 55 also exposes the first conductive circuit 41 and the second conductive circuit 43. After that, referring to FIGS. 3M to 3O, continue the removal step, the electrical connection layer formation step, the soldering portion formation step, and the conductive material filling step to complete the wafer-level ultrasonic wave of the second embodiment shown in FIG. 2 Sensing device 1.

As in the previous embodiments, the wafer-level ultrasonic sensing device 1 uses the hollow cavity 111 and the conductive material 60 to make the difference in the medium of the ultrasonic signal different in speed, so that the ultrasonic signal can be effectively Distinguish. In addition, through the configuration and manufacturing method of the substrate assembly 10, the alignment and bonding stability can be effectively improved, and the overall manufacturing yield can be effectively improved, thereby reducing the overall cost.

1: Wafer-level ultrasonic sensing device 10: Substrate assembly 10B: Composite substrate 101: First side surface 103: second side surface 11: First wafer 11b: bottom surface 111: Groove/hollow cavity 13: second wafer 13a: first surface 15: Insulation layer 17: The third wafer 20: Ultrasonic components 201: The first piezoelectric material layer 203: first electrode material layer 205: second piezoelectric material layer 207: second electrode material layer 21: The first ultrasonic unit 211: The first bottom piezoelectric layer 213: first electrode 215: The first piezoelectric layer 22: Ultrasonic components 221: first piezoelectric layer 222: first electrode 222a: upper surface 223: second piezoelectric layer 224: second electrode 224a: upper surface 23: The second ultrasonic unit 231: second bottom piezoelectric layer 233: second circuit pattern layer 235: second piezoelectric layer 237: second electrode 30: The first protective layer 30A: first contact hole 30B: second contact hole 41: The first conductive line 43: second conductive line 50: second protective layer 55: opening 60: Conductive material 71: The first electrical connection layer 73: second electrical connection layer 80: Welding Department 600: carrier board

FIG. 1 is a schematic cross-sectional view of a first embodiment of a wafer-level ultrasonic sensing device. 2 is a schematic cross-sectional view of a second embodiment of a wafer-level ultrasonic sensing device. 3A to FIG. 3O are schematic cross-sectional views corresponding to each step of the manufacturing method of the first embodiment of the wafer-level ultrasonic sensing device. 4A to 4H are schematic cross-sectional diagrams corresponding to the steps in the second embodiment of the wafer-level ultrasonic sensing device that are different from the first embodiment in the manufacturing method.

1: Wafer-level ultrasonic sensing device

10: Substrate assembly

101: First side surface

103: second side surface

11: First wafer

11b: bottom surface

111: Hollow cavity

13: second wafer

13a: first surface

22: Ultrasonic components

221: first piezoelectric layer

222: first electrode

222a: upper surface

223: second piezoelectric layer

224: second electrode

224a: upper surface

30: The first protective layer

41: The first conductive line

43: second conductive line

50: second protective layer

55: opening

60: Conductive material

71: The first electrical connection layer

73: second electrical connection layer

80: Welding Department

Claims (11)

A wafer-level ultrasonic sensing device includes: A substrate assembly includes a first wafer and a second wafer, wherein a groove is opened on the first wafer, and the second wafer is bonded to the first wafer and covers the groove, thereby defining a Hollow cavity An ultrasonic element located on the second wafer, and the ultrasonic element and the projection of the hollow cavity are superimposed in a vertical direction; A first protective layer located on a first surface of the second wafer and surrounding the ultrasonic element; A first conductive circuit and a second conductive circuit are located on the first protective layer and are respectively connected to an upper surface of the ultrasonic element, wherein the first wafer, the second wafer, and the first protective layer And the first conductive circuit are coplanar on a first side surface, and the first wafer, the second wafer, the first protective layer and the second conductive circuit are coplanar on a second side surface; A second protective layer covering the first conductive circuit and the second conductive circuit, the second protective layer having an opening, and the upper surface of the ultrasonic element corresponds to the opening; A conductive material located in the opening and in contact with the upper surface of the ultrasonic element; Two electrical connection layers are respectively disposed on the first side surface and the second side surface, and are connected to the first conductive circuit and the second conductive circuit; and The two soldering parts are located on a bottom surface of the first wafer and are respectively connected to the two electrical connection layers. The wafer-level ultrasonic sensing device according to claim 1, wherein the ultrasonic element includes a first piezoelectric layer, a first electrode, a second piezoelectric layer and sequentially stacked on the second wafer A second electrode, wherein the second piezoelectric layer and the second electrode do not cover part of the upper surface of the first electrode, the conductive material contacts the second electrode, and the first electrode and the second electrode are respectively connected to The first conductive circuit and the second conductive circuit are connected. The wafer-level ultrasonic sensing device according to claim 1, wherein the ultrasonic element includes a first ultrasonic unit and a second ultrasonic unit, wherein the first ultrasonic unit includes a first piezoelectric layer and a first electrode , The first piezoelectric layer is located on the second wafer, and the first piezoelectric layer and the first protective layer have a first contact hole connected, and the first electrode is covered on the first piezoelectric Layer, and a part of the first electrode is exposed to the first contact hole, a part of the first conductive circuit is located in the first contact hole, and is connected to the first electrode; the second ultrasonic unit is perpendicular to the second The direction of the wafer does not overlap with the first ultrasonic unit, and the second ultrasonic unit includes a second piezoelectric layer, a second circuit pattern layer, and a second electrode. The second piezoelectric layer is located on the second On the wafer, the second piezoelectric layer and the first piezoelectric layer are the same layer and separated from each other, the second circuit pattern layer is covered in the second piezoelectric layer, and the second circuit pattern layer is The first electrodes are in the same layer and separated from each other, the second electrode is located on the second piezoelectric layer, the first protection layer has a second contact hole, the second contact hole communicates with the opening, and the second conductive circuit A part of is located in the second contact hole and is connected to the second electrode, and a part of the conductive material is filled in the second contact hole and is in contact with the second electrode. The wafer-level ultrasonic sensing device according to claim 1, wherein the conductive material is polydimethylsiloxane. A manufacturing method of a wafer-level ultrasonic sensing device includes: A substrate preparation step provides a first wafer and a composite substrate. The first wafer is provided with a groove. The composite substrate includes a second wafer, an insulating layer, and a third wafer stacked in sequence. round; A bonding step, anodic bonding the second wafer and the first wafer, the second wafer covers the groove, so that the groove forms a hollow cavity; A removing step, removing the insulating layer and the third wafer thereon to complete a substrate assembly; An ultrasonic element forming step is to form an ultrasonic element on a second wafer, wherein the ultrasonic element and the projection of the hollow cavity are superimposed in a vertical direction, and the ultrasonic element includes a first electrode and is not connected to the A second electrode connected to the first electrode; A first protective layer forming step, forming a first protective layer on an upper surface of the ultrasonic element and the first surface of the second wafer, the first protective layer having a first contact hole and a second contact A hole, a part of the first electrode and a part of the second electrode are respectively exposed to the first contact hole and the second contact hole; In a circuit connection step, a first conductive circuit and a second conductive circuit are formed on the first protective layer, and a part of the first conductive circuit and the second conductive circuit are respectively disposed in the first contact hole and the second conductive circuit. In two contact holes, respectively connected to the first electrode and the second electrode of the ultrasonic element; A second protective layer forming step, forming a second protective layer to cover the first conductive circuit and the second conductive circuit; An opening opening step, opening an opening on the second protective layer, and at least a part of the second electrode is exposed in the opening; A removing step, removing a part of the substrate assembly, a part of the first protective layer, a part of the first conductive circuit, and a part of the second conductive circuit to form the first wafer and the second wafer , A first side surface of the first protective layer, the first conductive circuit coplanar, and a first wafer, the second wafer, the first protective layer, and the second conductive circuit coplanar Two-sided surface A step of forming an electrical connection layer, respectively forming an electrical connection layer on the first side surface and the second side surface, and the electrical connection layers are respectively connected to the first conductive circuit and the second conductive circuit; A step of forming a soldering portion, forming two soldering portions on a surface of the first wafer crystal plate, and each of the soldering portions is overlapped with each of the electrical connection layers; and In a conductive material filling step, a conductive material is filled in the opening, and the conductive material contacts the upper surface of the ultrasonic element. The method for manufacturing a wafer-level ultrasonic sensor device according to claim 5, wherein a polishing step is further included before the bonding step, and the polishing step reduces the thickness of the second wafer. The method for manufacturing a wafer-level ultrasonic sensing device according to claim 5, wherein after the opening opening step, a carrier covering step is further included, and the carrier covering step is to cover a carrier on the second protective layer To cover the opening; and after the step of forming the welding portion, a carrier removing step is further included to remove the carrier to expose the opening. The method for manufacturing a wafer-level ultrasonic sensing device according to claim 5, wherein the step of forming the ultrasonic element includes: Sequentially forming a first piezoelectric layer, a first electrode, a second piezoelectric layer, and a second electrode on the second wafer; and Remove a part of the second piezoelectric layer and the second electrode, wherein the second piezoelectric layer and the second electrode do not cover part of the upper surface of the first electrode, and in the opening opening step, it is further removed from the The first protective layer above the second electrode. The method for manufacturing a wafer-level ultrasonic sensing device according to claim 5, wherein the step of forming the ultrasonic element includes: Sequentially forming a first piezoelectric material layer and a first electrode material layer on the second wafer; The first piezoelectric material layer and the first electrode material layer are patterned to form a first bottom piezoelectric layer and a second bottom piezoelectric layer that are separated from each other, and are respectively stacked on the first bottom piezoelectric layer And a first electrode and a second circuit pattern layer on the second bottom piezoelectric layer; Sequentially forming a second piezoelectric material layer and a second electrode material layer on the first electrode and the second circuit pattern layer; and The second piezoelectric material layer and the second electrode material layer are patterned to form a first piezoelectric layer and a second piezoelectric layer that are separated from each other, and a first piezoelectric layer formed on the second piezoelectric layer Two electrodes, wherein the first electrode is covered in the first piezoelectric layer, and the second circuit pattern layer is covered in the second piezoelectric layer. The method for manufacturing a wafer-level ultrasonic sensing device according to claim 9, wherein the step of forming the first protective layer further includes: Forming a first protective material layer on the first piezoelectric layer, the second piezoelectric layer and the second electrode; and Perforating the first protective material layer to pattern the first protective material layer into the first protective layer, wherein the first protective layer includes the first contact hole and the second contact hole, the first contact hole Through the first protective layer and the first piezoelectric layer, a part of the first electrode is exposed in the first contact hole, and the second contact hole penetrates the first protective layer to expose a part of the second electrode In the second contact hole. The method for manufacturing a wafer-level ultrasonic sensing device according to claim 5, wherein the bonding step is performed in an evacuated environment.

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